The purpose of this experiment was to study the effects of cutting height on the quality of whole plant corn silage and explore the suitable cutting height for different corn varieties, which would provide a theoretical basis for producing and utilizing of whole plant corn silage. Three corn varieties widely cultivated in Heilongjiang province including high starch variety of Yangguang No.1, high protein variety of Zhongyuandan 32 and high biology yield variety of Longfu 208 were studied in this experiment. Using a single factor design, two cutting heights of 19 and 49 cm were set. There were 6 treatments with 3 replicates per treatment. Nutrient contents, fermentation quality and ruminal degradation rate at 24, 30 and 48 h were measured. The results showed as follows:1) about nutrient contents of whole plant corn silage, when the cutting height was increased from 19 cm to 49 cm, contents of crude protein (CP) and starch were significantly increased (P<0.05), while the contents of neutral detergent fiber (NDF) and acid detergent fiber (ADF) were significantly decreased in three corn varieties (P<0.05), and the contents of dry matter (DM) and ash of Yangguang No.1 and Longfu 208 were significantly increased (P<0.05). 2) There was no significant difference of pH among treatments (P>0.05). With the increase of cutting height, ammonia nitrogen/total nitrogen (NH₃-N/TN) of the same corn variety significantly decreased (P<0.05). NH₃-N/TN of Zhongyuandan 32 at cutting height of 49 cm was still significantly higher than that of Yangguang No.1 at cutting height of 19 cm (P<0.05), which indicated a higher protein decomposition in Zhongyuandan 32 at cutting height of 49 cm. At cutting heights of 19 and 49 cm, NH₃-N/TN of Yangguang No.1 was lower, which indicated a better fermentation quality of Yangguang No.1. For the contents of lactic acid and acetic acid, there were differences among different corn varieties, and cutting height had little effect on them. 3) With the increase of cutting height, ruminal dry matter degradation rate (DMD) and crude protein degradation rate (CPD) of all varieties of whole plant corn silage increased, while ruminal neutral detergent fiber degradation rate (NDFD) decreased. At cutting height of 49 cm, the 48 h ruminal DMD of Yangguang No.1 was the largest, had no significant difference with that at cutting height of 19 cm (P>0.05), and Yangguang No.1 had the largest 48 h ruminal NDFD at cutting height of 19 cm. The results indicate that increasing cutting height can improve DM, CP and starch contents of whole plant corn silage, but decrease NDF content, and decrease buffering capacity of fermentation process, thus has a little effect on fermentation indexes. Therefore, the cutting height of high starch variety of whole plant corn silage, such as Yangguang No.1, can be moderately dropped, so that the quality and yield can be raised; however, the cutting heights of high protein variety and high biology yield variety of whole plant corn silage, such as Zhongyuandan 32 and Longfu 208, can be increased properly to improve the quality of silage.